In connection with the distribution of bakery products, such as bread loaves, rolls, etc., conventional practice involves the initial loading of product packages onto trays or shallow baskets. (For convenience, both trays and baskets will be referred to herein as trays). The loaded trays are then inserted onto wheeled transport racks comprised of a series of vertically spaced opposed pairs of tray-supporting brackets mounted at opposite sides of a rack frame structure. Commonly, the tray supporting brackets are long enough to hold two trays, and adjacent sets are separated vertically by a relative minimum distance to accommodate one above the other without interference. In a typical case, a rack may hold 30 or more trays, for example, in 15 levels of two trays each. After being loaded with trays, the transport racks are wheeled onto the delivery trucks, which carry them to the retail stores.
In the process of automating bakery operations, one of the most difficult and intransigent operations has been that of loading the transport racks with trays filled with bakery products. The process has resisted automation in part because of the relatively crude, non-standardized character of the racks themselves, as well as because of the condition of the racks and trays after a period of time in service. For example, in a given rack, the vertical spacing between pairs of tray-supporting brackets may not be uniform. Indeed, the height of the brackets of an opposed pair may not even be the same. In addition, after racks have been in service for a period of time, some of the tray-holding brackets may become bent or otherwise damaged. In addition to the foregoing, while the racks used by a particular bakery may be generally similar in size and configuration, different bakeries typically may use racks of entirely different configuration.
An "obvious" solution to the problem of non-standardization in the transport racks would be to provide, for automation purposes, a redesigned rack of highly standardized construction, manufactured to acceptable tolerance levels. However, bakeries have in circulation enormous numbers of the existing transport racks, and the economics of replacing all of such racks would be prohibitively expensive.
In accordance with the present invention, a novel and improved method and apparatus is provided for automated loading of bakery transport racks, which effectively deals with the racks in their existing, non-standardized, non-ideal configurations, while enabling totally automated, high speed loading of the transport racks with trays filled with bakery products.
Pursuant to one aspect of the invention, an empty transport rack, in preparation for loading, is scanned vertically along opposite sides, by an optical or other suitable scanner device which detects the presence of each tray-holding bracket and records its vertical height in relation to a known reference. The respective heights of each bracket of each opposed pair are compared, and the higher of the two serves as the basis for a stored height location for that pair of brackets. In addition, the difference between the vertical height measurements for the two brackets of a pair is compared against a reference standard. If the difference in vertical height is excessive, so that a tray could not be properly supported by the bracket pair, that fact is registered in a temporary data base so that, during loading, that bracket pair is by-passed.
In accordance with another aspect of the invention, during the initial scan of a transport rack presented for loading, the distance required to complete the scan of a given bracket is compared against a predetermined standard. If the distance is indicated to be excessive, as compared to the standard, that is an indication that the bracket is bent or deformed, and that fact is registered in the temporary data base, so that the defective bracket is by-passed during loading.
During the above described optical scan of a newly presented transport rack, an acoustical scan is also made of the rack, in order to detect the presence of any trays which may have inadvertently been left on the rack and would prevent the loading of a new tray at the same location. If any such residual trays are detected the location thereof is registered in the temporary data base for subsequent control of the rack loading operations.
Pursuant to another aspect of the invention, a loading mechanism is provided, which includes a lifting mechanism onto which trays, filled with product, are pre-loaded. The lift mechanism comprises opposed pairs of tray-holding brackets movable vertically and controllably driven in accordance with data stored in the temporary data base, in order to deliver loaded trays to preselected levels opposite a usable set of brackets on the transport rack to be loaded. In conjunction with the tray lift mechanism, a pusher mechanism is provided, which is vertically movable independently of the lift mechanism, and is movable to a location at which a tray, filled with product, is properly aligned with a usable set of brackets on the transport rack. The pusher serves to move the tray from the lift mechanism onto the brackets of the transport rack.
In a typical case, the transport rack is of a two-deep construction, capable of receiving two trays on each set of brackets. To this end, the pusher mechanism is constructed for two stage operation, so that, at each usable bracket location, a first tray is pushed to the back of the transport rack, and a second tray is pushed to the front position on the rack.
Desirably, the pusher mechanism includes both a tray gripping means and a load sensing element. In cases where the pusher mechanism encounters unexpected resistance, such resistance is immediately sensed by the load sensing element. The pusher mechanism is retracted and the tray is withdrawn, and the temporary data base is revised to indicate by-passing of that rack location.
During loading of a transport rack, and also during the time interval when a filled rack is removed and replaced by an empty rack, trays filled with bakery products arrive at the load station via a conveyor system and are pre-loaded onto bracket pairs of the lift mechanism. Thus, at any time, the lift mechanism may be holding several of the pre-loaded trays. The design of the system is such that trays are transferred from the elevator mechanism to the transport racks at a rate greater than trays arrive via the conveyor system, so that trays do not progressively accumulate on the elevator mechanism. During removal and replacement of the transport racks, however, several trays may accumulate on the elevator mechanism. According to another aspect of the invention, after an empty transport rack is installed at the loading position and has been scanned with respect to the location and condition of its tray-holding brackets and possible residual trays, a loading schedule is automatically constructed, based upon the registered locations of usable brackets and positions of the transport rack and the number and location of trays, filled with product, that have been pre-loaded onto the elevator mechanism. This schedule is prepared by computer algorithm, which then governs the loading of the transport rack then in position to be loaded.
Among other conditions, the program seeks to load the transport rack from the bottom up, with minimum vertical motion of the elevator mechanism and, to the extent possible, avoiding moving any tray on the elevator mechanism above any empty usable bracket position on the transport rack. A highly efficient, high speed loading procedure is realized by this technique.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of a preferred embodiment and to the accompanying drawings.